Design, Simulation and Characterization of Compliant Microfluidic Devices
thesisposted on 28.06.2013 by Tatjana Dankovic
In order to distinguish essays and pre-prints from academic theses, we have a separate category. These are often much longer text based documents than a paper.
A new technique has been developed to make valves and other microfluidic structures by patterned welding of compliant thermoplastic films. Electrical contacts, packaging, and low leakage connections with external tubing to these structures have also been demonstrated. An electrostatically driven normally open microvalve made of thermoplastic materials is presented. The microvalves are compatible with a wide range of fluids. The microvalve is limited to actuation voltages less than 600 V because of the breakdown voltage limitation of 1.4 µm thick Mylar film. The pressure range is limited by the value of the closing voltages to few kPa, although the valve can withstand much higher applied pressures (~20 kPa). The operating temperature should be limited to 100 ºC because of the low melting point of the LLDPE tubing and support rings. The measured leak rate for well manufactured microvalves was less than 10% of the flow rate. The proposed fabrication method for welding very thin polyester sheets is used to produce several types of micromixers and demonstrate its potential use for producing different designs of mixer structures that can be modified as needed without the need for a photolithography or microfabrication facilities. The proposed fabrication technique is applicable for the design of the planar microfluidic devices.